1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * net/sched/em_text.c Textsearch ematch |
4 | * |
5 | * Authors: Thomas Graf <tgraf@suug.ch> |
6 | */ |
7 | |
8 | #include <linux/slab.h> |
9 | #include <linux/module.h> |
10 | #include <linux/types.h> |
11 | #include <linux/kernel.h> |
12 | #include <linux/string.h> |
13 | #include <linux/skbuff.h> |
14 | #include <linux/textsearch.h> |
15 | #include <linux/tc_ematch/tc_em_text.h> |
16 | #include <net/pkt_cls.h> |
17 | |
18 | struct text_match { |
19 | u16 from_offset; |
20 | u16 to_offset; |
21 | u8 from_layer; |
22 | u8 to_layer; |
23 | struct ts_config *config; |
24 | }; |
25 | |
26 | #define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data) |
27 | |
28 | static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m, |
29 | struct tcf_pkt_info *info) |
30 | { |
31 | struct text_match *tm = EM_TEXT_PRIV(m); |
32 | int from, to; |
33 | |
34 | from = tcf_get_base_ptr(skb, layer: tm->from_layer) - skb->data; |
35 | from += tm->from_offset; |
36 | |
37 | to = tcf_get_base_ptr(skb, layer: tm->to_layer) - skb->data; |
38 | to += tm->to_offset; |
39 | |
40 | return skb_find_text(skb, from, to, config: tm->config) != UINT_MAX; |
41 | } |
42 | |
43 | static int em_text_change(struct net *net, void *data, int len, |
44 | struct tcf_ematch *m) |
45 | { |
46 | struct text_match *tm; |
47 | struct tcf_em_text *conf = data; |
48 | struct ts_config *ts_conf; |
49 | int flags = 0; |
50 | |
51 | if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len)) |
52 | return -EINVAL; |
53 | |
54 | if (conf->from_layer > conf->to_layer) |
55 | return -EINVAL; |
56 | |
57 | if (conf->from_layer == conf->to_layer && |
58 | conf->from_offset > conf->to_offset) |
59 | return -EINVAL; |
60 | |
61 | retry: |
62 | ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf), |
63 | conf->pattern_len, GFP_KERNEL, flags); |
64 | |
65 | if (flags & TS_AUTOLOAD) |
66 | rtnl_lock(); |
67 | |
68 | if (IS_ERR(ptr: ts_conf)) { |
69 | if (PTR_ERR(ptr: ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) { |
70 | rtnl_unlock(); |
71 | flags |= TS_AUTOLOAD; |
72 | goto retry; |
73 | } else |
74 | return PTR_ERR(ptr: ts_conf); |
75 | } else if (flags & TS_AUTOLOAD) { |
76 | textsearch_destroy(conf: ts_conf); |
77 | return -EAGAIN; |
78 | } |
79 | |
80 | tm = kmalloc(size: sizeof(*tm), GFP_KERNEL); |
81 | if (tm == NULL) { |
82 | textsearch_destroy(conf: ts_conf); |
83 | return -ENOBUFS; |
84 | } |
85 | |
86 | tm->from_offset = conf->from_offset; |
87 | tm->to_offset = conf->to_offset; |
88 | tm->from_layer = conf->from_layer; |
89 | tm->to_layer = conf->to_layer; |
90 | tm->config = ts_conf; |
91 | |
92 | m->datalen = sizeof(*tm); |
93 | m->data = (unsigned long) tm; |
94 | |
95 | return 0; |
96 | } |
97 | |
98 | static void em_text_destroy(struct tcf_ematch *m) |
99 | { |
100 | if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config) { |
101 | textsearch_destroy(EM_TEXT_PRIV(m)->config); |
102 | kfree(EM_TEXT_PRIV(m)); |
103 | } |
104 | } |
105 | |
106 | static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m) |
107 | { |
108 | struct text_match *tm = EM_TEXT_PRIV(m); |
109 | struct tcf_em_text conf; |
110 | |
111 | strncpy(p: conf.algo, q: tm->config->ops->name, size: sizeof(conf.algo) - 1); |
112 | conf.from_offset = tm->from_offset; |
113 | conf.to_offset = tm->to_offset; |
114 | conf.from_layer = tm->from_layer; |
115 | conf.to_layer = tm->to_layer; |
116 | conf.pattern_len = textsearch_get_pattern_len(conf: tm->config); |
117 | conf.pad = 0; |
118 | |
119 | if (nla_put_nohdr(skb, attrlen: sizeof(conf), data: &conf) < 0) |
120 | goto nla_put_failure; |
121 | if (nla_append(skb, attrlen: conf.pattern_len, |
122 | data: textsearch_get_pattern(conf: tm->config)) < 0) |
123 | goto nla_put_failure; |
124 | return 0; |
125 | |
126 | nla_put_failure: |
127 | return -1; |
128 | } |
129 | |
130 | static struct tcf_ematch_ops em_text_ops = { |
131 | .kind = TCF_EM_TEXT, |
132 | .change = em_text_change, |
133 | .match = em_text_match, |
134 | .destroy = em_text_destroy, |
135 | .dump = em_text_dump, |
136 | .owner = THIS_MODULE, |
137 | .link = LIST_HEAD_INIT(em_text_ops.link) |
138 | }; |
139 | |
140 | static int __init init_em_text(void) |
141 | { |
142 | return tcf_em_register(&em_text_ops); |
143 | } |
144 | |
145 | static void __exit exit_em_text(void) |
146 | { |
147 | tcf_em_unregister(&em_text_ops); |
148 | } |
149 | |
150 | MODULE_DESCRIPTION("ematch classifier for embedded text in skbs" ); |
151 | MODULE_LICENSE("GPL" ); |
152 | |
153 | module_init(init_em_text); |
154 | module_exit(exit_em_text); |
155 | |
156 | MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT); |
157 | |